Tooth for dental plates.



F. Z. HANSCOM.

TOOTH FOR DENTAL PLATES.

APPLICATION FILED APR. 1. 19H.

1 ,1 98,842, Patented Sept. 19, 1916.

UNITED STATES PATENT OFFICE.

FRANK Z. HANSCOM, OF CHICAGO, ILLINOIS.

TOOTH FOR DENTAL PLATES.

To all whom it may concern:

Be it known that I, FRANK Z. HANSCOM, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Teeth for Dental Plates, of which the following is a speci fication.

This invention relates to artificial teeth in connection with plates formed of rubber or other suitable material, and more particularly to the form of such teeth and means for forming a strong and substantial attachment of the teeth with the plate.

.Among the objects of the present invention are to provide teeth which may be securely held in the plate, without the use of pins; to form the engaging ends of the teeth in such manner that they will be securely gripped and held by the material of the plate in which they are embedded; to arrange the engaging ends of the teeth so that there will preferably be a positive line of contact between the outer surface of the plate surrounding the teeth and the teeth and avoiding thin contact edges of the plate, adjacent to the teeth, thereby enabling the plate to be polished around the edges of the teeth without danger of injuring the plate or exposing the contact or holding portion of the teeth and thereby improving the sanitary features of the plate; to utilize as fully as possible the portion of the platewhich may be made thickest and heaviest,

.- for holding the teeth; and 'to provide such other novel features of construction and advantages as will appear from the following description.

In the accompanying drawings illustrating my inventionFigure l is a side view of a plate provided with teeth embodying this invention, a portion of the plate being broken away to illustrate the method of holding the teeth; Fig. 2 is an enlarged side view of an anterior tooth; Fig. 3 is a rear view of the same; Fig. t is a sectional View of the same; Fig. 5 is a side view of a posterior tooth, with a portion of the plate shown in dotted lines; Fig. 6 is a plan view of the tooth shown in Fig. 5; and Fig. 7 is a sectional view of the same.

I have found that in certain forms of artificial teeth heretofore in common use, there has been little or no effort made to arrange the base or root portion of the tooth so that it will be firmly held by the Specification of Letters Patent. P t t d S t. 19, 19 Application filed April 1, 1911. i i

Serial No. 818,466.

plate, as pins have been relied upon to hold the teeth in position.

In accordance with my present invention, I shape the holding portion of the tooth in such manner that the rubber or other material of which the plate may be made will flow around this holding portion and enter grooves or depressions around the sides of the same, so that when the material hardens the tooth will be firmly held and will be braced, as it were, in all directions. For lnstance, as shown in the drawings, the teeth 8 are held in the plate 9 by having the engaging portions 10 of the teeth so shaped that when embedded in the material of the plate the teeth will be held securely in position. It will be noted that the form of the teeth is varied in accordance with natural requirements, and likewise, the engaging portion may be varied for the difierent forms of teeth from the frontal or anterior teeth to the back or posterior teeth. For instance, the frontal tooth 11 is pro vided, at its base or engaging end, with a groove 12, preferably extending across the top or cervical end of the tooth and down the sides thereof, as indicated in Figs. 1 to This groove is preferably somewhat undercut, and the sides of the engaging portion 10 are preferably somewhat converging, as indicated in Fig. 3, so that this engaging portion is narrower at its lower end than at the upper end. This engaging portion is also formed so that it will project inwardly or into the material of the plate as far as possible where the plate may be made thickest; therefore, the lower part of the engaging portion, as indicated at 13, Fig. 2, is extended inwardly to form a substantial heel or projection which may be firmly embedded in the rubber for the plate. As clearly indicated at 14, Figs. 1 and 2, the material of the plate comes to a rather abrupt edge where it surrounds the base of the tooth, and as this line of contact or division coincides with the outer edge of the groove 12, it will be noted that there is no thin edge or fin of the-rubber surrounding the face or cervical end of the tooth as is commonly seen in ordinary construction heretofore used. Furthermore, on account of having this abrupt line of division, the

operator in making the teeth may readily polish the surface of the plate, without liability of uncovering or exposing the engaging end or portion of the tooth.

As indicated in Figs. 5, 6 and 7, the posterior tooth 15 is provided with a groove 16 which extends around the labial side of the tooth and about half-way across the sides, where it preferably terminates in somewhat dovetail shaped pockets 17, which extend partially, down the sides of the tooth, the base or inner surface of these pockets be ing preferably made substantially V-shaped, as clearly shown at 18, Figs. 5 and 6. These pocket-like recesses are also preferably provided, at places where the tooth has the greatest amount of body, with inwardly extending holes 19. At the labial side of the tooth is an extension or projection 20 which extends partially around this side of the tooth to form a shoulder for assisting in holding the tooth securely in position. The cervical end 21 of the tooth 15, or the inner surface of the holding portion, is preferably formed to correspond in general with the curvature of the surface of the plate and is also made narrower adjacent to the pockets or recesses 17 than at its outer end.

From the above description of typical forms of my improved teeth and from the accompanyingdrawings, it will be readily seen that when the material of the plate has surrounded the engaging ends 10 of the teeth, it will flow into the groove 12 of the tooth l1 and into the groove 16 and side depressions of the tooth 15 and will also extend somewhat below or beyond the labial or inwardly extending projections 13 and 20, respectively, of these forms of teeth, thereby firmly embracing and holding the teeth in position when such material has become hardened. On account of the peculiar forms of the engaging portions 10, the teeth will be braced, as it were, in every direction, so that they cannot readily become loosened, and on account of making this engaging portion so that it will extend as far as possible into the body of the material where it is thickest and strongest, there will be little danger or liability of the plate being weak ened at the points where the teeth are inserted.

It will be readily observed that it is necessary to change the shape and form of the various teeth and correspondingly to vary the engaging portions thereof, and therefore I do not wish to limit myself to the particular form or shape herein shown and de scribed, except as set forth in the appended claims, but

What I claim and desire to secure by Letters Patent is:

1. A tooth for plates, having a groove on its cervical end, extending across the buccal side and approximately half way across each of the adjacent sides, whereby the material of the plate which surrounds the engaging portion of the tooth will flow into the groove, in order to hold the tooth firmly in position, and will terminate at the outer edge of the groove.

2. A tooth for plates, having an undercut groove extending substantially half-way around one end thereof and terminating in inwardly extending clove-tail recesses, the opposite side of said tooth being provided with an outwardly extending projection whereby the material of the plate will flow into the groove and recesses and around said projection in order to hold the tooth firmly in position.

3. A tooth for plates, having an undercut groove on its cervical end extending across the buccal side and approximately half way across each of the adjacent sides, the portion of the tooth circumscribed by said groove, being wider at the buccal side than at the ends of the groove.

FRANK Z. HANSCOM.

Vitnesses C. H. PLUMB, KATHERINE CLUxToN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

